Flush valves are used selectively to control the flushing of a urinal or toilet with a certain fixed volume of water. Typically, flush valves include a flexible diaphragm which forms a seal between the inlet and outlet, whereby a disruption of the diaphragm will result in a flow of water into the urinal or toilet to evacuate the waste.
Commercial toilets and urinals have traditionally utilized a single flush volume in their operations. This flush volume is designed to provide the maximum amount of water needed to clear solid waste products. However, solid waste and liquid waste generally require different volumes of water to be cleared from the bowl. In a single flush system, the higher volume of water necessary to flush solid waste is also used to flush liquid waste, with the result that more water than is necessary is often used. Ideally, the smallest amount of water necessary to achieve an adequate flushing of the waste would be utilized.
While multi-flush volume valves are known and allow for a more efficient flush, they only achieve this efficiency if the appropriate flush mode is used. These known valves are manually activated. In such systems, the proper flush volume is determined by the user; thus, manual actuation of the flush valve often results in an improper choice of flush volume. Users may be unaware of the dual flush system and, thus, do not appropriately use it. In addition, users may be aware of the system, but simply give no thought to how they are actuating the flush valve, but instead activate the device as they have in the past.